It is known, for example, from the DATA SHEET "Three-Phase Brushless DC Motor Driver L6231" published in the SGS data book MOTION CONTROL APPLICATION MANUAL, (January 1987, pages 641 through 647) that for triggering (controlling) multi-winding electric motors its individual windings are provided with current in cyclic fashion.
Triggering signals are usually of such a nature that one current is impressed upon each of the windings in dependence upon the angular position, .phi., of a rotor of the electric motor. The current changes direction dependent upon the position .phi.. Between the time periods during which a corresponding current is being impressed, time periods are provided during which the individual windings are without current. If one designates the state of the first direction of current as +1, the second state as -1 and the current-less or no-current state as 0, then, in the case of a first example for a trigger signal, the states +1, 0, -1, 0, +1 etc. ensue in cyclic fashion for a particular winding.
Triggering impulses applied to the other windings always exhibit, in dependence upon their number, a phase difference with reference to the position .phi. compared to the first triggering signal. They, too, usually exhibit the states +1, 0, -1, 0, 1 etc. in cyclic fashion.
However, strong interference impulses appear, particularly at transitions between the states +1, 0 and -1, 0, which impulses must be attenuated.
In the SGS data book cited, on the one hand, suitable combinations of resistors and capacitors, so-called RC elements, have been suggested for interference suppression, which combinations are disposed at the output terminals of the high-power (final) drive stages for the triggering of the motor. Typically these suppression networks are coupled between the power drive stage (may be realized in the form of an integrated circuit) and the motor winding connections. Alternatively, the SGS data book specifies integrators with suitable feedback capacitors as a means for interference suppression, which integrators are located ahead of the drive circuits and may be included at least in part within an integrated circuit.
The foregoing suppression circuits may be realized as part of the triggering circuit. However, if they are realized as part of an integrated circuit they occupy significant active circuit area and undesirably reduce the integration density.